Lookup variable in globals if not found in pyclass scope, see ticket #671

Cython/Compiler/ExprNodes.py

@@ -1529,12 +1529,24 @@ class NameNode(AtomicExprNode):
                 namespace = Naming.builtins_cname
             else: # entry.is_pyglobal
                 namespace = entry.scope.namespace_cname
+            if not self.cf_is_null:
                 code.putln(
-                '%s = PyObject_GetItem(%s, %s); %s' % (
+                    '%s = PyObject_GetItem(%s, %s);' % (
                         self.result(),
                         namespace,
-                interned_cname,
-                code.error_goto_if_null(self.result(), self.pos)))
+                        interned_cname))
+            if self.cf_maybe_null:
+                if not self.cf_is_null:
+                    code.putln('if (unlikely(!%s)) {' % self.result())
+                    code.putln('PyErr_Clear();')
+                code.putln(
+                    '%s = __Pyx_GetName(%s, %s);' % (
+                    self.result(),
+                    Naming.module_cname,
+                    interned_cname))
+                if not self.cf_is_null:
+                    code.putln("}");
+            code.putln(code.error_goto_if_null(self.result(), self.pos))
             code.put_gotref(self.py_result())
 
         elif entry.is_pyglobal or entry.is_builtin:

Cython/Compiler/FlowControl.py

@@ -474,7 +474,7 @@ def check_definitions(flow, compiler_directives):
             node.cf_maybe_null = True
             if not entry.from_closure and len(node.cf_state) == 1:
                 node.cf_is_null = True
-            if node.allow_null or entry.from_closure:
+            if node.allow_null or entry.from_closure or entry.is_pyclass_attr:
                 pass # Can be uninitialized here
             elif node.cf_is_null:
                 if (entry.type.is_pyobject or entry.type.is_unspecified or

tests/errors/w_uninitialized_class.pyx

-# cython: warn.maybe_uninitialized=True
-# mode: error
-# tag: werror
-# class scope
-
-def foo(c):
-    class Foo(object):
-        if c > 0:
-            b = 1
-        print a, b
-        a = 1
-    return Foo
-
-_ERRORS = """
-10:15: local variable 'a' referenced before assignment
-10:18: local variable 'b' might be referenced before assignment
-"""

tests/run/pyclass_scope_T671.py

+# mode: run
+# ticket: 671
+
+A = 1234
+
+class SimpleAssignment(object):
+    """
+    >>> SimpleAssignment.A
+    1234
+    """
+    A = A
+
+class SimpleRewrite(object):
+    """
+    >>> SimpleRewrite.A
+    4321
+    """
+    A = 4321
+    A = A
+
+def simple_inner(a):
+    """
+    >>> simple_inner(4321).A
+    1234
+    """
+    A = a
+    class X(object):
+        A = A
+    return X
+
+def conditional(a, cond):
+    """
+    >>> conditional(4321, False).A
+    1234
+    >>> conditional(4321, True).A
+    4321
+    """
+    class X(object):
+        if cond:
+            A = a
+        A = A
+    return X
+
+def name_error():
+    """
+    >>> name_error() #doctest: +ELLIPSIS
+    Traceback (most recent call last):
+    ...
+    NameError: ...B...
+    """
+    class X(object):
+        B = B
+
+def conditional_name_error(cond):
+    """
+    >>> conditional_name_error(True).B
+    4321
+    >>> conditional_name_error(False).B #doctest: +ELLIPSIS
+    Traceback (most recent call last):
+    ...
+    NameError: ...B...
+    """
+    class X(object):
+        if cond:
+            B = 4321
+        B = B
+    return X
+
+C = 1111
+del C
+
+def name_error_deleted():
+    """
+    >>> name_error_deleted() #doctest: +ELLIPSIS
+    Traceback (most recent call last):
+    ...
+    NameError: ...C...
+    """
+    class X(object):
+        C = C